When invoked so as to spawn a shell, pasta checks explicitly for the
shell being bash and if so, adds a "-l" option to make it a login shell.
This is not ideal, since this is a bash specific option and requires pasta
to know about specific shell variants.
There's a general convention for starting a login shell, which is to
prepend a "-" to argv[0]. Use this approach instead, so we don't need
bash
specific logic.
Signed-off-by: David Gibson <david(a)gibson.dropbear.id.au>
---
pasta.c | 32 ++++++++++++++++++++------------
1 file changed, 20 insertions(+), 12 deletions(-)
diff --git a/pasta.c b/pasta.c
index 1dd8267..97cd318 100644
--- a/pasta.c
+++ b/pasta.c
@@ -148,10 +148,12 @@ void pasta_open_ns(struct ctx *c, const char *netns)
/**
* struct pasta_setup_ns_arg - Argument for pasta_setup_ns()
+ * @exe: Executable to run
* @argv: Command and arguments to run
*/
struct pasta_setup_ns_arg {
- char **argv;
+ const char *exe;
+ char *const *argv;
};
/**
@@ -162,12 +164,13 @@ struct pasta_setup_ns_arg {
*/
static int pasta_setup_ns(void *arg)
{
- struct pasta_setup_ns_arg *a = (struct pasta_setup_ns_arg *)arg;
+ const struct pasta_setup_ns_arg *a;
FWRITE("/proc/sys/net/ipv4/ping_group_range", "0 0",
"Cannot set ping_group_range, ICMP requests might fail");
- execvp(a->argv[0], a->argv);
+ a = (const struct pasta_setup_ns_arg *)arg;
+ execvp(a->exe, a->argv);
perror("execvp");
exit(EXIT_FAILURE);
@@ -182,26 +185,31 @@ static int pasta_setup_ns(void *arg)
void pasta_start_ns(struct ctx *c, int argc, char *argv[])
{
struct pasta_setup_ns_arg arg = {
+ .exe = argv[0],
.argv = argv,
};
- char *shell = getenv("SHELL");
- char *sh_argv[] = { shell, NULL };
- char *bash_argv[] = { shell, "-l", NULL };
char ns_fn_stack[NS_FN_STACK_SIZE];
+ char *sh_argv[] = { NULL, NULL };
+ char sh_arg0[PATH_MAX + 1];
c->foreground = 1;
if (!c->debug)
c->quiet = 1;
- if (!shell)
- shell = "/bin/sh";
if (argc == 0) {
- if (strstr(shell, "/bash")) {
- arg.argv = bash_argv;
- } else {
- arg.argv = sh_argv;
+ arg.exe = getenv("SHELL");
+ if (!arg.exe)
+ arg.exe = "/bin/sh";
+
+ if ((size_t)snprintf(sh_arg0, sizeof(sh_arg0),
+ "-%s", arg.exe) >= sizeof(sh_arg0)) {
+ err("$SHELL is too long (%u bytes)",
+ strlen(arg.exe));
+ exit(EXIT_FAILURE);
}
+ sh_argv[0] = sh_arg0;
+ arg.argv = sh_argv;
}
pasta_child_pid = clone(pasta_setup_ns,
--
2.37.3